Flow valve



June 11, 1940.

H.v C. GLITSCH ET AL www vAnvs Fi1ed Apri; 26, 1957 sheets-sheet :a

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June ll, 1940. H. c. GLlTscH ET A. 5 2,203,957

no w VALVE `Filed April 2,6, 1937 3 Sheets-Sl'leet4 5 l/ V/V/// I Stimm',

Patented June 11, I

UNITED STATES FLow vALvii Hans c. autsch and charles s. crickmer, nanas, Tex., asslgnors to Merla Tool Company, Dallas,

Tex., a lim of Texas Application April 26,( 1937, Serial No. 138,920 16 Claims. (Cl. 103-232) This invention relates to new and useful improvements in ilow valves.

One object of the invention is' to provide an improved valve forcontrolling the admission of Kl a lifting fluid into awell tubing to raise the liquid in said tubing to the surface, said valve being au-4 tomatic in its operation. l

An important object of the invention is to'pro- Vvide an improved flow valve including a plunger '10 for controlling the admission of lifting fluid to fthe well tubing, said plunger having one side exposed to the lifting uid pressure and its opposite side exposed tothe pressure of the well liquid, whereby the plunger is operated by the l5 dilerential in said pressures.

Another object of the invention is to provide an improved flow valve having a plunger` which has one end of larger cross-sectional area than the opposite end, the greater area being exposed 2o to the well liquid while the smaller area is exposed to the lifting iluid, whereby the pressure of lifting iluid must be several times greater than ythe pressure of the liquid before .the plunger is moved,

which makes thefvalve particularly adaptable for .25 use in low pressure wells and assures that the lifting uid can lift the column of liquid built up.

, A further object of the invention is to provide an improved plunger for controlling the admission of a lifting fluid into a well tubing to lift the liquid, saidI plunger being tubular to provide a passage for the flow of'incoming liquid, whereby the velocity of the admitted fluid acts directly -on said plunger to aid in moving it to its closed position.

Still another object of the invention is to pro'- vide an improved plunger of the character described, the actuation of the plunger being controlled by the dilierential in the pressure of the lifting iuid and the pressure of the well liquid,

with auxiliary resilient means capable of vadjustmentfor positively actuating said plunger when a predetermined pressure diiierential is reached.V

wherein:4 I 1 Figure lis a view partly in elevation and partly.

in section showing a plurality of ilow valves, constructedin accordance with the invention contnected ina well tubing. y 5g FigureZ is a transverse-vertical sectionalview taken through the flow valve and showing the l same in its `@closed position, [l

Figure 3 is a similar view showing the valve in y its open position,

Figure 4 is a horizontal cross-sectional view 5 taken on the line 4 4 of Figure 3,

Figure 5 is a view similar to Figure 3 showing another form of the invention4 in a closed position,

Figure 6 is a view similar to Figure 5, with the valve open to permit admission of a lifting `iiuid lo into the well tubing,

Figure 7 is a horizontal cross-sectional view taken on the line l--T of Figure 5,4 and Figure 8 is a horizontal, cross-sectional view,

Alifting uid such as gas or air is admitted toy the well casing through an inlet pipe I3 which connects in the casing head Il and manifestly,

said lifting nuid fuls the annular space between 2g the casingand the tubing. Each now valve'assembly is arranged to admit the lifting fluid from the annular space-liuto the tubing in order to lift the well liquid which rises in said tubing. The position of the valves A in the well tubing is, of course, dependent upon theparticular condition of the well.

Each valve assembly A includes an elongate sleeve lll which has its upper end internally threaded at I5, whereby it may be connected into 3g the tubing string. The lower end ofthe sleeve Ilis provided -with external screw-threads Ill which threads receive the upper end of a section of the tubing I2. A radially extendingbosa tl is preferably formed integral with the upper end 4g of the sleeve Il at one side thereof and said boss is provided with an internally screw-threaded bore I8 at its lower end. A recess or chamber |19 is formed within the boss above the bore I B and this recess communicates through a radial port 2li w with the interior of the sleeve Il Vand therefore,l with the interior-of the weil tubing I2. A similar boss 2l is provided near the lower end of the sleeve I4 being located in vertical alinement with the boss I'I. -The boss 2l is provided with a vertical w opening 22 which is substantially the same diameter asthe bore Il.

A cylinder 23 has its upper end screw-threaded into the bore Il of the boss Il and when so connected in the boss theupper end of said cylinder w ,the same as the external diameter of the cylinder 23, whereby said collar forms a continuation of the cylinder. The collar is inserted into the opening 22 in the lower boss 2| and preferably has a snug flt therein. Obviously, the collar 26 serves to brace and support the lower end of the cylinder 23. It is pointed out that said collar could be` made integral with said cylinder, but for purposes of assembly and dis-assembly, it is preferable to make the two parts separate.

The cylinder 23 is formed with an axial bore 26 which extends from the lower end of said cylinder to a point substantially mid-height thereof. The upper end of the bore 26 is enlarged as shown at 26 whereby an internal annular shoulder 2'I4 is formed within the cylinder 23. The vextreme lower end of the bore 26 is provided with an annular bevel or' seat 29, as is clearly shown in Figures 2 and 3. A plunger or piston 29 has av sliding t within the bore 26 of the cylinder 23 and is formed with a head 39 at its lower end. When the plunger is'in a raised position within thecylinder, as

shown in Figure 2, the head 39 is arranged to en-` Sage the seat 29 at the lower end of the bore 26, whereby a flow of fluid from the annular space between the casing I9 and tubing I2 through the collar 25 and bore 26, is prevented. The upper end of the plunger 29V is externally screw-'threaded and a piston 3| is connected thereto. The piston is slidable vertically ln the enlarged portion 26' of the bore of the cylinder and said piston has an axial bore 32 into which the upper end of the plunger 29 is threaded. The bore 32 of the piston is enlarged as shown at 32 whereby an upstanding collar or flange is, in eifectJ provided at the upper end of said piston.

The plunger -29 -is provided with an axial bore V2li' which is substantially of the same diameter as the bore 32.of the piston, whereby it forms a continuation of said bore. The bore 29' extends from v the upper end of the plunger toa point just above the head 39 at the lower end of said plunger. Radial ports 33 located above the head 39 extend inwardly through the wall of the plunger 29 and communicate with the lower end of the axial bore 29' of said plunger. By observing Figure 2,

it will be seen that when the. plunger is in its raised position the ports 33 are within the lower endof the bore 26 of the cylinder and therefore the lifting fluid such as gas' or air which is present in theannular space between the casing I9 and the tubing I2 cannot iiow into' the ports 33. However, when the plunger 29 is moved'to its lower position as shown in Figure 3, the ports'33 are moved outof .the bore 26 of-the cylinder 23 and into the elongate collar 25. When in this position the lifting fluid may enter the ports '.33 and flow upwardly through the bore 29' of the plunger, then through the 4bores 32 and 32" of the piston 3|, after which it may enter the chamber I9 and flow through the port 29 into the interior of the well tubing I2. Thus, the position of the plunger positively controls the'admission of the lifting fluid to the interior of the tubing.`

tional area of the ,fluid but,- by properly arranging the desired pressure of the liquid may open the valve. This makes the valve particularly adaptable for spider as which is disposed transversely within the interior of the elongate' collar 26. Y The extreme lower end of the stem 3l is screw-threaded to receive a pair of nuts 36 and a coiled spring 31 is interposed between the spider 364 and-the 5 nuts 36. 'Ihis spring surrounds the stem and exerts its pressure to constantly urge the plunger 29 and piston 3| downwardly within the cylinder 23. The tension on the spring 31 may of course, be varied by merely adjusting the nuts 36 on said stem. v

Assuming the parts to be in the position shown in Figure 2 with the annular space between the well casing I9 and the tubing I2 lled with the lifting fluid such as gas or air, and with no well liquid within the tubing I2, it will'be manifest that the lifting fluid will act upon the cross-sechead 39- of the plunger 29, to hold the plunger' and the piston 3| connected therewith in its raised position against the tension of the coiled spring 31. The parts will remain in this position until such time as' the well liquid builds up in the tubing to a point above the port 29. The pressure ofthis liquid within the tubing is of course exerted on the upper yend of the piston 3| through the port 29 and chamber I9. ASince the cross-sectional area of the piston 3| is greater than the cross-sectional area of the head 39, it will be obvious that when the liquid within the tubing builds u'p to a predetermined proportion of the pressure of the lifting a fluid, said liquid will tend to move the piston 3| and plunger `29 downwardly. Therefore, if the pressure of the lifting iluid in the well casing I9 is 300 pounds,.the cross-sectional areas of the piston 3| and head 39 may beof such size that a 50-pound pressure of the wellliquid within the tubing I2 will start the plunger downwardly. It is not necessary for the well liquid to build up a pressure in excess of the pressure of the lifting areas, any

use in wells having a low pressure or a low-liquid level. l Y

When the pressure of the liquid within the tubing reaches a predetermined'proportion of the pressure of the lifting fluid, the piston -3I and plunger 29 are moved downwardly whereby the ports 33 at the lower end of the plunger 29 are -moved out ofthe bore 26 of the cylnder 23. When this, occurs the lifting fluid from within'the casing I9 will flow upwardly through the collar 25 into the ports 33, upwardly through the plunger and piston, and ilnally into the well tubing through the port 29. This admitted lifting fluid will of coursev lift the-well liquid upwardly within vthe tubing.

Since the lifting fluid is owing through the ,plunger 29, it lwill be manifest that the `velocity of the flow of this iluid will act on said plunger and will tend to raise the plunger upwardly. 'As soon asv the load of the liquid column is lightened due to the admission of the lifting fluid, the pressure above the piston 3| is reduced which changes the differential across the piston andplunger. Since the pressure of the lifting fluid is' constant in the well casing, said lifting nuid acting against the cross-sectional area of the head 39 will move the plunger to its raised position. This move-7o lnient will of course be assisted by thevelocity of the fluid flowing throughthe plunger bore'29' for naturally as the load is lightened the velocity of flow of the lifting fluid through the plunger bore will be' increased. As the plunger moves to 75 its upper position, the'head 3|lA engages the seat 28 to again cut off jt-he flow of the lifting fluid.l The parts remain in this position until such time y as the liquid again builds up a sufdcient pressure to move the plunger downwardly. In the event that any fluid or liquid should become trapped below the* piston 3| and above the shoulder 21 upon operation of the valve, upon the next movement of the piston and plunger, this trapped liquid or fluid may escape from beneath the piston through a spring-operated check valve 38 which is formed in the lower end of the piston at one side thereof. It is iointed out that the coiled -spring 31 aids the liquid pressure in moving the valve to its-open position and therefore byini6 is shown. In this form the sleeve |4 is connectedA I der,4|i. This sleeve or stem is preferably formed l face is arranged to engage the shoulder 44'. The

in the tubing string I2 and is provided with the upper boss |1 and the lower boss` 2|; In place of the cylinder 23 and its associate parts, a cylinder has its upper endkthreaded into the bore I8 of the upper boss. The lower end of the .f

cylinder 40 is inserted into the vertical opening 22 of the lower boss 2| and the open end of the cylinder is closed by a cap member 4| which a continuation thereof and fits snugly withiny the opening 22. The cap member 4| is' provided with wardly therefrom into and axially of the cylinintegral with the cap yand is provided with an axial bore 43 extending throughout its length. The bore 43 is of the same diameter as the upper portion of thebore 4|' ofthe cap 4| whereby it is a continuation thereof. The lower end of the bore 4| of the cap 4| is enlarged as indicated at 44 whereby an internal annular shoulder 44' is vformed within lthe cap 4|. y I

A valve member is slidable vertically in the enlarged portion 44 of the bore and is provided with a conical face 46 at its' upper end, which valve member 45 is provided or formed with a plurality of vertical grooves or channels 41 so that when said valve is in its lowered position as' shown in Figure 6,.the lifting fluid within the well casing may enter the bore 44 of the cap,4|,

Vvfrom where it may flow upwardly through the bore 43 of the axial sleeve 42. Of course when the valve member 45 is engaging the shoulder` 44', a flow of the lifting fluid throughthe bore An elongate piston 48 is movable vertically within the cylinder 40 and has an axial bore 49 through which the sleeve 42 extends. Manifestly the vertical movement of the piston v48 is guided by the axial sleeve. A transverse web or spider 50n extends across thev upper end of the piston 48 and an elongate stem 5|, which is preferably made integral 4with the valve member 45 and which extends-upwardly through the bore 43 of 4 -the sleeve 42, has its upper end secured to the central portion of said web, `whereby the web and valve member t5 are fastened together. A coiled The operation ofthisform of the invention is substantially the same as the loperation of the form shown in Figures l Ito 4. With the parts in the -position shown in Figure 5 the fluid pressure in the well casing is acting against the crosssectional area of .the valve member 45 to hold said valve member against the seat 4t', whereby admission ofthe lifting fluid to the well tubing I2 is prevented. As the well liquid column builds up in the tubing, the pressure of said liquid acts through the port 20 and chamber it and the boss Il and downwardly against the top of the piston 48 as well as against the cross-sectionalarea of" the valve face 46which is exposed through or within the bore 43 of the guide sleeve d2. The

` combined area of the piston, stem and valve face 46 is of course much greater than the crosssectional area of the valve member 45 and therefore the pressure of the liquid is acting against a much greater area Vthan the area against which the lifting fluid is acting. Therefore as soon as the pressure of the liquid builds up a predetermined proportion of the lifting fluid pressure,

'. the pistonlliand spider 50 will be moved downlwardly within the cylinder 40. As this occurs member is threaded into, said lower end. The diameter ofthe cap member is substantially the. same as that of the cylinder 48 whereby it forms:`

the valve member 45 will also be moved downwardly becausetof the connection of the yspider I' with said member'through the stem 5|. As the valve is unseated, the lifting fluid will flow up- A -e wardly through the vertical grooves 41 in the pean axial sleeve orstem 42 which extends up-1 '-'f riphery of the member 45, after which it will flow through the sleeve 42 into the upper end of the cyan-der, and finally through theV port zu into "the well. tubing, whereby -the liquid within said tubing'is lifted. The valve member 45 will re- 4Inadriin this position until'such time as the load :in the tubing is lightened and the pressilre above the piston A4|! decreased'. When said pressure decreases to a predetermined point, the lifting fluid pressuremin the casing acting againstthe underlside of thev valve member 45, will immediately move the valve niembei'to Iits seated position to cut off further owof the lifting fluid.

It is pointed` 'out that in both forms a most simple `structure for controllingthe admission of the lifting uido'is provided." 4Assembly or disassembly'of th`es`valve-is readilymade'V for the purposes of repair or for other reasons. e In both instances a single member controls the flow of the lifting fluid to the tubing and also in both instances, the liquid is acting against a greater cross-sectional area than is the lifting fluid. With sucharrangement, it is not necessary for the liquidl to' buildup an excessive pressure within` the tubing before the lifting fluid is admitted and therefore assurance is had at all'times that the lifting fluid will be sufficient to raise the column ofr liquid whichhas built up in the tubing. What we claim and desire to secure by Letters Patent is: f

1. A, flow valve -including, a tubular bodyV adapted to be `connected in a tubing string and having a passage for establishingl communication betweenthe interior and exterior-of the tubing, a member' movable within the passage and having one end exposed to the pressure in the interior of the tubing and its opposite end exposed to the the passage, and resilient means for urging the y member to its open position andarranged to add its pressure to the pressure within the tubing and acting therewith against the exterior pressure.

2. A now vaive inc-hiding, a tubular body.

adapted to be connected" in a tubing string and having a passage for establishing communication between the interior and exterior of the tubing,

a member movable within the passage and having one end exposed to the pressure in the interior of the tubing and its oppositeend exposed to the pressure exterior of the tubing, said ends being of different cross-sectional areas, whereby saidmember is moved by a predetermined .differential in such pressures to .control the vflow through the passage, resilient means for urging the member to its open position and arranged to add its pressure 'to the pressure within the tubing and acting therewith against the exterior pressure, and means for adjusting said resilient means to control within certain limits the differential necessary to impart movement to the member.VA

3. A flow valve including, a tubular body adapted to be connected in a tubing which extends axially within a well casing, said body having a port establishing communication between the interior of the tubing and the interior of the lcasing,-a cylinder mounted on the sides of the body and having its upper end communicating with the port and its lower end communicating with the interior of the well casing, and a movable member mounted in the borev of .the cylinder for closing the lower end thereof and having one end exposed to the pressure in the tubing and its oppositeend exposed to the pressure in the casing, said ends having different cross-sec-- body and having its upper end communicating with the port 'and its lower` end communicating with the interior of the well casing, a movable member mounted in the bore of the cylinder for y ing a port establishing communication between closing the lower end thereof and having one end exposed to thepressure in the tubing and its opposite end exposed to the pressure in the casing, said ends'having .different cross-sectional areas whereby when the pressure Ain the tubing reaches a predetermined proportion of the pressure in the casing said member is actuated to establish communicationbetween the interior or' the tubing and the interior of' the casing, and resilient means acting on said member to aid the pressure within the casing' the pressure within the tubing in acting against 5. A flow valve including, a tubular adapted to be connected in a tubing which extends axially within a well casing, said body havthe interior of the tubing and the interior of the casing, a cylinder mounted on the side of the` body and having its upper end communicating with the port and its lower end communicating with the interior of the well casing, a movable member mounted in the bore of the cylinder for closing the lowerend thereof and having one end exposed to the pressure in the tubing and its opposite end exposed to the pressure in the casing, said ends-having different cross-sectional areas whereby when the pressure in the tubing reaches a predetermined proportion of the pressure in the casing said member is actuated to establish communicationl between the interior of the tubing and the interior of the` casing, resilient means acting yon said member to aid the pressure within the tubing in acting, against the pressure within theA casing, and means for adjusting said resilient means to vary the pressure differential necessary to actuate the valve.

6.' A flow valve including,4 a tubular body adapted to be connected in a -well tubing having a well influent inlet and extending axially of a well casing, means for introducing a lifting fluid into said casing, said body having a port estab` lishing communication between the interior of' the well tubing and casing, a cylinder on the body having a bore which communicates with-the ,port, and a tubular plunger slidable within the when loweredv and having its upper end exposed to the pressure of the well influent and its lower end exposed to the lifting fluid, said upper end` being of greater cross-sectional area than the4 lower end whereby when the infiuent pressure reaches a predetermined proportion of the lifting fluidY pressure the plunger is moved to permit V`a flow of lifting fluid through the tubular plunger and into the tubing to lift the influent therein.

7. A flow valve including, a tubular body adapted to be connected in a well tubing having a well influent inlet and extending axially of a well casing, means for introducing a lifting fluid into g said casing, saidy body having a port establishing communication between the interior of the well tubing and casing, a cylinder on the body having a bore which communicates with the port,

' and altubular plunger closing the lower end of the bore of the cylinder and having radial inlet ports at its lower end which ports are closedmined proportion of the lifting fluid, the plunger ,is moved downwardly to uncover' the inlet ports and permit a flow of lifting fluid through the tubular plunger cylinderv bore and into the interior of the tubing to raise `the influent therein.

v8. A flow valve including, a tubular body adapted to be connected in a well tubing having a well influent inlet and extending axially of a well casing, means for introducing a, lifting fluid into said casing, said body having a port establishing comm'unication between the interior of the well tubing and casing, acylinder on the body having a bore whichfcommunicates with the port, a tubularplunger closing the lower end of the bore of the cylinder and having radial inlet ports at its lower end which ports are closed by` the cylinder wall when the plunger is in a raised position, said plunger having its upper end exposed tothe pressure of the influent and lits lower end exposed to the pressure of the lifting fluid, the upper end being of greater cross-sectional area than the lower end, whereby, when the pressure of the influent reaches a predetermined proportion of the lifting fluid, the plunger is moved downwardly to uncover the inlet ports and permit a flow of lifting fluid through the tubular plunger cylinder bore and into the interior of the tubing to raise the influent therein, and resilient means yfor constantly urging the plunger to its lowered position and aiding the influent pressure to overcome the lifting fluid pressure.

9. A flow valve including, a tubular body adapted to be connected in a well tubing having a well influent inlet and extending axially of a well casing, means for introducing a lifting fluid into said casing, said body having a port establishing communication between'the interior of the the upper end being of greater cross-sectional area than the lower end, whereby, when the pressure of the influent reaches a predetermined proportion of the lifting fluid, the plunger is moved downwardly to uncover the` inlet ports ann permit aflow of lifting fluid through the tubular plunger cylinder bore and into the interior of the tubing to raise the influent therein, resilient' means for constantly urging the plunger 'to its lowered position and aiding the-influent pressure to overcome the lifting fluid pressure, and means for adjusting said resilient means -to vary the` pressure differential necessary to move the plunger.

10. A flow valve including,` a tubular body* adapted to be connected in a well tubing having a well influent inlet and extending axially of 'a wellcasing, means for introducing a lifting fluid into said casing, said body having`a port estab- .lishing communication between the interior of the well tubing and casing, Aa cylinder on the body having a borewhich communicates with the port, a closme for the lower end of the cylinder and having'an axial bore establishing communication between thev well casing andl cylinder,

a-valve membe'i' for closing the axial bore of the;

closure and subjected to the pressure of the lifting fluid within the casing, a piston having a greater' cross-'sectional area than the member' and ex'- posed to the pressure of the well fluid, and means for 'connecting the piston with vthe member,

`whereby the piston and member are moved to open the bore of the ,closure when the pressure of the well influent reaches apredetermined Droportion of the pressure of the lifting fluid to permit a flow of lifting fluid from the well casing through the bore of the closure and through the cylinder into the interior of the tubing to lift the influent therein.

1l. A vflow device including,l a tubular body adapted to be' connected in a tubing which extends axially within a well casing, said body having a port establishing communication between the4 interior of the tubing and interior of the well casing,-

a sleeve mounted on the side of the body and having communication with the port and having its lower end communicating with the interior ofthe well casing, a pressure responsive means mounted in the bore of the sleeve and exposed to the pressure in the tubing, and a valve head having a fixed connection with the` pressure responsive means for closing the lower end of the bore and exposed to the pressure in the casing, e said means and valve head having different crosssectional areas, whereby when the pressure in the tubing reaches a predetermined proportion of the pressure in the casing, said means is actuated to move said head and establish communication i between the interior of the tubing and the interior of the casing.

1,2. A flow` device including, a tubular body adapted to be connected in a well tubing having a well influentinlet and extending axially of .a well l5 casing, means for introducing a liftingfluld into, said casing, the body having a port establishing communication between the interior of the well tubing and casing, a sleeve on the body having a -bore which communicates with theport, aclosure on the sleeve for the lower end of the sleeve and having an axial bore establishing communication between the well casing and sleeve, a valve head for closing the axial bore ofthe closure and subjected to the pressure of the lifting fluid within the casing, a pressure responsive means having l a greater cross-sectional areathan the head and Lexposed to the pressure of the well influent, and means for rigidly connecting the pressure' responsive means with the head, whereby the means and the head are moved simultaneously to open the bore fof the closure. when the pressure of the well influent reaches a predetermined proportion of the pressure of the lifting fluid to permita ow of lifting fluid from the well casing through the boreof the closure and through the sleeve into the interior of the tubing to lift the influent therein. f

. 13, A flow device including, a tubular body adapted to be connected in a"1 tubing string and 40 having a passage for establishing communication between the interior and exterior of the tubing,

a valve having a by-pass therethrough within the passage andA arranged to be moved` to open and close the by-pass to control the admittance of a lifting fluid to the tubing, said-valve having one side exposed to the lifting fluid pressure, and

a piston slidable in `thepassage and having conv nection with the valve and exposed to the presl sure in the interior of the tubing, said piston be- Z ing of a different area than the valve, whereby the piston and valve are moved by a predetermined differential vin` such pressures. to control the flow throughthe passagej 14. A ow device including, a tubular body adapted to be connected in a tubing string and having a passage for establishing ,communication between the interior and exterior of the tubing, Il

by the piston andyalve are 'moved by a predetermined differential in such pressures, the piston having a bi1-pass for the lifting fluid, which bypass is opened and closed by the position of the valve, whereby said valve controls the admita tance of the lifting fluid through the by-pass andinto` the tnbing. y

15. A now device including, a tubuiaigbcciy adapted to be connected in a tubing which ex-Il .75

within 4a well casing. a sleeve 'tends axially y mounted on the side of the body and having communication with the interior of the well tubing and casing, means for controlling the flow through tlepassage to control the admittance of a lifting uid to the tubing and having one side thecontrol means is in a closed'position, li

,exposed to the lifting iluid pressure, and a piston slidable within the sleeve and having connection with said control means and exposed to the pressure in the interior of the tubing, said control means and piston having a bil-Dass for by-passing the fluid therethrough when the means is in an open position, the by-pass being closed when said passage.

tends axially within a. well casing,A a sleeve removably mounted having communication with the interior of the well tubing and casing, a valve having a sliding vfit in the passage for controlling the flow therethrough to control the admittance of a lifting fluid to the tubing' and having one side exposed to the lifting uid pressure, and a piston slidable in the bore of the sleeve and having connection with said valve and exposed to the pressure in the interior of the tubing. said piston' having a by-pass forfby-passing the lifting iluid therethrough when the valve is inan open position, said piston being of a different cross-sectional area than the valve, whereby' said piston and valve are moved byl a predetermined differential in such pressures to control the flow through the HANS C. GLITSCH. CHARLES S. CRICKMER.

on the side of the body and 

